Japan has shut down its last working nuclear reactor for a scheduled maintenance without specifying a potential date for the restart.
The shut down of reactor 4 at Kansai Electric Power's Ohi nuclear power station in Fukui prefecture in western Japan, leaves the country without nuclear power supply for the second time in 40 years.
The move follows public's hostility towards atomic power after the meltdowns at Tokyo Electric Power's Fukushima Daiichi plant in March 2011.
Despite public opposition, Japan's Prime Minister Shinzo Abe has openly supported the use of nuclear energy calling it a vital part of his plan to boost the economy.
Federation of Electric Power Cos chairman Makoto Yagi was quoted by Bloomberg as saying that Japan may not have enough capacity in winter without nuclear power.
Around ten regional power companies are still assessing winter power demand and supply, Yagi added.
The reactor was restarted in July last year following closure in March 2012 to help address the country's increased electricity demand during the winter primarily in the western region.
Japan is using costly fossil-fuel alternatives to generate electricity after the shutdown of all of its 50 atomic plants in May 2102 for scheduled inspection, with company's unable to restart them due to public opposition.